Model Simone Holtznagel works out her 'non-existent a**' at new boyfriend Jono Castano's gym

Jono Castano is his own best advertisement in a pair of undies

Celebrity personal trainer Jono Castano cuddles up to model girlfriend Simone Holtznagel

Jono Castano's ex-wife Amy teases new love interest as she shares image of man tugging at G-string